The invention relates to devices for indicating when a predetermined number of events have occurred, and automatically starting a new count of events only after the activity is completed. Such devices find special application, for example, in vending equipment for products or services such as washing or drying of clothing, which is rendered operable by deposit of a given number of coins which are counted by a coin accumulator. Desirably such a coin accumulator arrangement may be readily adjusted to provide a vending control signal only after deposit of an arbitrarily selected number of coins, where the number is easily adjusted by a maintenance procedure, and is limited only by the capacity of the accumulator.
Adjustable mechanical devices for counting coins have been made, but require the changing of cams, gears, or levers to program a number of coins required for operation. This reprogramming or adjustment is a relatively difficult task; and to minimize complexity and cost, these devices have a counting capacity which is limited to a very small number of coins.
One common difficulty with coin counting mechanisms is that the coin detection device, especially when it is a mechanical switch, is affected by mechanical shock. This problem may arise if a user of the equipment provides a sharp blow to the area around the coin slot, hoping to cause a sticking coin to drop. A variation of this problem commonly encountered is that the deposit of a single coin provides multiple signals because of contact bounce. This variation is also more of a problem if the equipment is struck while a coin is passing through the mechanism.
It is of course desirable that the counting mechanism start from zero when power is first applied to the equipment. A further problem arises when there is a power interruption during the course of counting coins. Mechanical and electro-mechanical systems, as used to date, are generally designed to reset to zero at the time of power interruption. The count of coins already deposited by a customer is then lost. This source of customer dissatisfaction has not previously been adequately corrected.